import { Request, Response, NextFunction } from "express";
import { z } from "zod";
import { db, exitNodes, sites } from "@server/db";
import { clients, clientSites } from "@server/db";
import response from "@server/lib/response";
import HttpCode from "@server/types/HttpCode";
import createHttpError from "http-errors";
import logger from "@server/logger";
import { eq, and } from "drizzle-orm";
import { fromError } from "zod-validation-error";
import { OpenAPITags, registry } from "@server/openApi";
import {
    addPeer as newtAddPeer,
    deletePeer as newtDeletePeer
} from "../newt/peers";
import {
    addPeer as olmAddPeer,
    deletePeer as olmDeletePeer
} from "../olm/peers";
import axios from "axios";

const updateClientParamsSchema = z
    .object({
        clientId: z.string().transform(Number).pipe(z.number().int().positive())
    })
    .strict();

const updateClientSchema = z
    .object({
        name: z.string().min(1).max(255).optional(),
        siteIds: z
            .array(z.string().transform(Number).pipe(z.number()))
            .optional()
    })
    .strict();

export type UpdateClientBody = z.infer<typeof updateClientSchema>;

registry.registerPath({
    method: "post",
    path: "/client/{clientId}",
    description: "Update a client by its client ID.",
    tags: [OpenAPITags.Client],
    request: {
        params: updateClientParamsSchema,
        body: {
            content: {
                "application/json": {
                    schema: updateClientSchema
                }
            }
        }
    },
    responses: {}
});

interface PeerDestination {
    destinationIP: string;
    destinationPort: number;
}

export async function updateClient(
    req: Request,
    res: Response,
    next: NextFunction
): Promise<any> {
    try {
        const parsedBody = updateClientSchema.safeParse(req.body);
        if (!parsedBody.success) {
            return next(
                createHttpError(
                    HttpCode.BAD_REQUEST,
                    fromError(parsedBody.error).toString()
                )
            );
        }

        const { name, siteIds } = parsedBody.data;

        const parsedParams = updateClientParamsSchema.safeParse(req.params);
        if (!parsedParams.success) {
            return next(
                createHttpError(
                    HttpCode.BAD_REQUEST,
                    fromError(parsedParams.error).toString()
                )
            );
        }

        const { clientId } = parsedParams.data;

        // Fetch the client to make sure it exists and the user has access to it
        const [client] = await db
            .select()
            .from(clients)
            .where(eq(clients.clientId, clientId))
            .limit(1);

        if (!client) {
            return next(
                createHttpError(
                    HttpCode.NOT_FOUND,
                    `Client with ID ${clientId} not found`
                )
            );
        }

        if (siteIds) {
            let sitesAdded = [];
            let sitesRemoved = [];

            // Fetch existing site associations
            const existingSites = await db
                .select({ siteId: clientSites.siteId })
                .from(clientSites)
                .where(eq(clientSites.clientId, clientId));

            const existingSiteIds = existingSites.map((site) => site.siteId);

            // Determine which sites were added and removed
            sitesAdded = siteIds.filter(
                (siteId) => !existingSiteIds.includes(siteId)
            );
            sitesRemoved = existingSiteIds.filter(
                (siteId) => !siteIds.includes(siteId)
            );

            logger.info(
                `Adding ${sitesAdded.length} new sites to client ${client.clientId}`
            );
            for (const siteId of sitesAdded) {
                if (!client.subnet || !client.pubKey) {
                    logger.debug(
                        "Client subnet, pubKey or endpoint is not set"
                    );
                    continue;
                }

                // TODO: WE NEED TO HANDLE THIS BETTER. RIGHT NOW WE ARE JUST GUESSING BASED ON THE OTHER SITES
                // BUT REALLY WE NEED TO TRACK THE USERS PREFERENCE THAT THEY CHOSE IN THE CLIENTS
                const isRelayed = true;

                // get the clientsite
                const [clientSite]  = await db
                    .select()
                    .from(clientSites)
                    .where(and(
                        eq(clientSites.clientId, client.clientId),
                        eq(clientSites.siteId, siteId)
                    ))
                    .limit(1);

                if (!clientSite || !clientSite.endpoint) {
                    logger.debug("Client site is missing or has no endpoint");
                    continue;
                }

                const site = await newtAddPeer(siteId, {
                    publicKey: client.pubKey,
                    allowedIps: [`${client.subnet.split("/")[0]}/32`], // we want to only allow from that client
                    endpoint: isRelayed ? "" : clientSite.endpoint 
                });

                if (!site) {
                    logger.debug("Failed to add peer to newt - missing site");
                    continue;
                }

                if (!site.endpoint || !site.publicKey) {
                    logger.debug("Site endpoint or publicKey is not set");
                    continue;
                }

                let endpoint;

                if (isRelayed) {
                    if (!site.exitNodeId) {
                        logger.warn(
                            `Site ${site.siteId} has no exit node, skipping`
                        );
                        return null;
                    }

                    // get the exit node for the site
                    const [exitNode] = await db
                        .select()
                        .from(exitNodes)
                        .where(eq(exitNodes.exitNodeId, site.exitNodeId))
                        .limit(1);

                    if (!exitNode) {
                        logger.warn(
                            `Exit node not found for site ${site.siteId}`
                        );
                        return null;
                    }

                    endpoint = `${exitNode.endpoint}:21820`;
                } else {
                    if (!endpoint) {
                        logger.warn(
                            `Site ${site.siteId} has no endpoint, skipping`
                        );
                        return null;
                    }
                    endpoint = site.endpoint;
                }

                await olmAddPeer(client.clientId, {
                    siteId: site.siteId,
                    endpoint: endpoint,
                    publicKey: site.publicKey,
                    serverIP: site.address,
                    serverPort: site.listenPort,
                    remoteSubnets: site.remoteSubnets
                });
            }

            logger.info(
                `Removing ${sitesRemoved.length} sites from client ${client.clientId}`
            );
            for (const siteId of sitesRemoved) {
                if (!client.pubKey) {
                    logger.debug("Client pubKey is not set");
                    continue;
                }
                const site = await newtDeletePeer(siteId, client.pubKey);
                if (!site) {
                    logger.debug(
                        "Failed to delete peer from newt - missing site"
                    );
                    continue;
                }
                if (!site.endpoint || !site.publicKey) {
                    logger.debug("Site endpoint or publicKey is not set");
                    continue;
                }
                await olmDeletePeer(
                    client.clientId,
                    site.siteId,
                    site.publicKey
                );
            }
        }

        await db.transaction(async (trx) => {
            // Update client name if provided
            if (name) {
                await trx
                    .update(clients)
                    .set({ name })
                    .where(eq(clients.clientId, clientId));
            }

            // Update site associations if provided
            if (siteIds) {
                // Delete existing site associations
                await trx
                    .delete(clientSites)
                    .where(eq(clientSites.clientId, clientId));

                // Create new site associations
                if (siteIds.length > 0) {
                    await trx.insert(clientSites).values(
                        siteIds.map((siteId) => ({
                            clientId,
                            siteId
                        }))
                    );
                }
            }

                // get all sites for this client and join with exit nodes with site.exitNodeId
                const sitesData = await db
                    .select()
                    .from(sites)
                    .innerJoin(
                        clientSites,
                        eq(sites.siteId, clientSites.siteId)
                    )
                    .leftJoin(
                        exitNodes,
                        eq(sites.exitNodeId, exitNodes.exitNodeId)
                    )
                    .where(eq(clientSites.clientId, client.clientId));

                let exitNodeDestinations: {
                    reachableAt: string;
                    sourceIp: string;
                    sourcePort: number;
                    destinations: PeerDestination[];
                }[] = [];

                for (const site of sitesData) {
                    if (!site.sites.subnet) {
                        logger.warn(
                            `Site ${site.sites.siteId} has no subnet, skipping`
                        );
                        continue;
                    }

                    if (!site.clientSites.endpoint) {
                        logger.warn(
                            `Site ${site.sites.siteId} has no endpoint, skipping`
                        );
                        continue;
                    }

                    // find the destinations in the array
                    let destinations = exitNodeDestinations.find(
                        (d) => d.reachableAt === site.exitNodes?.reachableAt
                    );

                    if (!destinations) {
                        destinations = {
                            reachableAt: site.exitNodes?.reachableAt || "",
                            sourceIp: site.clientSites.endpoint.split(":")[0] || "",
                            sourcePort: parseInt(site.clientSites.endpoint.split(":")[1]) || 0,
                            destinations: [
                                {
                                    destinationIP:
                                        site.sites.subnet.split("/")[0],
                                    destinationPort: site.sites.listenPort || 0
                                }
                            ]
                        };
                    } else {
                        // add to the existing destinations
                        destinations.destinations.push({
                            destinationIP: site.sites.subnet.split("/")[0],
                            destinationPort: site.sites.listenPort || 0
                        });
                    }

                    // update it in the array
                    exitNodeDestinations = exitNodeDestinations.filter(
                        (d) => d.reachableAt !== site.exitNodes?.reachableAt
                    );
                    exitNodeDestinations.push(destinations);
                }

                for (const destination of exitNodeDestinations) {
                    try {
                        logger.info(
                            `Updating destinations for exit node at ${destination.reachableAt}`
                        );
                        const payload = {
                            sourceIp: destination.sourceIp,
                            sourcePort: destination.sourcePort,
                            destinations: destination.destinations
                        };
                        logger.info(
                            `Payload for update-destinations: ${JSON.stringify(payload, null, 2)}`
                        );
                        const response = await axios.post(
                            `${destination.reachableAt}/update-destinations`,
                            payload,
                            {
                                headers: {
                                    "Content-Type": "application/json"
                                }
                            }
                        );

                        logger.info("Destinations updated:", {
                            peer: response.data.status
                        });
                    } catch (error) {
                        if (axios.isAxiosError(error)) {
                            logger.error(
                                `Error updating destinations (can Pangolin see Gerbil HTTP API?) for exit node at ${destination.reachableAt} (status: ${error.response?.status}): ${JSON.stringify(error.response?.data, null, 2)}`
                            );
                        } else {
                            logger.error(
                                `Error updating destinations for exit node at ${destination.reachableAt}: ${error}`
                            );
                        }
                    }
                }

            // Fetch the updated client
            const [updatedClient] = await trx
                .select()
                .from(clients)
                .where(eq(clients.clientId, clientId))
                .limit(1);

            return response(res, {
                data: updatedClient,
                success: true,
                error: false,
                message: "Client updated successfully",
                status: HttpCode.OK
            });
        });
    } catch (error) {
        logger.error(error);
        return next(
            createHttpError(HttpCode.INTERNAL_SERVER_ERROR, "An error occurred")
        );
    }
}